Unicode routines (UTF8, UTF16, UTF32) and Base64: billions of characters per second using SSE2, AVX2, NEON, AVX-512, RISC-V Vector Extension. Part of Node.js and Bun. (by simdutf)

Simdutf Alternatives

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NOTE: The number of mentions on this list indicates mentions on common posts plus user suggested alternatives. Hence, a higher number means a better simdutf alternative or higher similarity.

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simdutf reviews and mentions

Posts with mentions or reviews of simdutf. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-12-25.
  • Decoding UTF8 with Parallel Extract
    1 project | | 5 May 2024
    IIRC all of the simdutf implementations use a lot of lookup tables except for the AVX512 and RVV backens.

    Here is e.g. the NEON code:

  • Glibc Buffer Overflow in Iconv
    1 project | | 21 Apr 2024
  • Vectorizing Unicode conversions on real RISC-V hardware
    1 project | | 27 Jan 2024
    The project was mostly inspired by simdutf [0] which has been around for a couple of years already, and I don't think iconv has any of its vectorized implementations for other architectures.


  • Cray-1 performance vs. modern CPUs
    4 projects | | 25 Dec 2023
    I'm actually doing something quite similar in my, in progress, unicode conversion routines.

    For utf8 validation there is a clever algorithm that uses three 4-bit look-ups to detect utf8 errors:

    Aside on LMUL, if you haven't encountered it yet: rvv allows you to group vector registers when configuring the vector configuration with vsetvl such that vector instruction operate on multiple vector registers at once. That is, with LMUL=1 you have v0,v1...v31. With LMUL=2 you effectively have v0,v2,...v30, where each vector register is twice as large. with LMUL=4 v0,v4,...v28, with LMUL=8 v0,v8,...v24.

    In my code, I happen to read the data with LMUL=2. The trivial implementation would just call vrgather.vv with LMUL=2, but since we only need a lookup table with 128 bits, LMUL=1 would be enough to store the lookup table (V requires a minimum VLEN of 128 bits).

    So instead I do six LMUL=1 vrgather.vv's instead of three LMUL=2 vrgather.vv's because there is no lane crossing required and this will run faster in hardware: (see [0] for a relevant mico benchmark)

            # codegen for equivalent of that function
  • What C++ library do you wish existed but hasn’t been created yet?
    18 projects | /r/cpp | 8 Jul 2023
    utf8 normalization, stemming, case insensitive comparison. example for rust What are options for C++? 1. translate to utf16 ( ) and use icu -- slow 2. boost text, , also slow (because the author doesn't care or couldn't care), we made a lot of patches to make our library faster than lucene, but still this part is slower than icu for utf16 (icu for utf16 also very slow...)
  • [Preprint] Transcoding Unicode Characters with AVX-512 Instructions
    1 project | /r/asm | 29 Mar 2023
    You can find the corresponding assembly code in this repository. The main branch only contains implementations based on C++ with intrinsics.
  • What's everyone working on this week (10/2023)?
    11 projects | /r/rust | 6 Mar 2023
    The next big thing is making it LSP-compatible. All language servers must implement UTF-16 based character offsets, which is kinda unfortunate considering that files are much more likely to be stored in UTF-8 (I think?). I don't want to do the UTF-8 -> UTF-16 transcoding, so instead I'll use the excellent simdutf library to count how much code points a UTF-8 string would take if it was transcoded into UTF-16 — which is much faster than actual transcoding. So this is what I'm going to do this week — rewriting parsers to produce UTF-16 offsets + some final benchmarking. After that is done, I'll consider the "research" part of this project completed and will start writing an actual Markdown parser.
  • Why would a language not natively support SIMD?
    1 project | /r/C_Programming | 17 Feb 2023
    You can find the assembly code here: The corresponding C++ code is in the main branch.
  • High speed Unicode routines using SIMD
    1 project | | 3 Sep 2022
  • text-2.0-rc1 with UTF8 underlying representation is available for testing!
    1 project | /r/haskell | 20 Nov 2021
    Or via an ultrafast simdutf.
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Basic simdutf repo stats
10 days ago

simdutf/simdutf is an open source project licensed under Apache License 2.0 which is an OSI approved license.

The primary programming language of simdutf is C++.

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